Volumetric machine



July 6, 1965 P. E. MERCIER 3,192,865

VOLUMETRIC MACHINE Original Filed Aug. 8, 1961 3 Sheets-Sheet 1 Pierre Ernest Marcia! INVENTOR BY WJZJJM ATTORNEYS July 6, 1965 P. E. MERCIER VOLUMETRIC MACHINE 3 Sheets-Sheet 2 Qriginal Filed Aug. 8. 1961 FIG 2 Pierre Emufflcrcicr INVENTOR BY WMM 446: *8

ATTQRNEZIS y 1965 P. E. MERCIER 3,192,866

VOLUMETRIC MACHINE Original Filed Aug. 8, 1961 3 Sheets-Sheet 3 FIGS Pierre Ernest Marcia l N V E N TO R AT TORN EYS United States Patent 3,192,866 VOLUMETRiC M'ACHEIIE Pierre Ernest Mercier, Piscop by Saint Brice, France,

assignor to Societe Anonyme Andre Citroen, Paris,

France Griginal application Aug. 8, 1961, Ser. No. 130,055, now

Patent No. 3,899,223, dated July 38, 1963. Divided and this application Feb. 11, 1963, Bar. No. 257,633 Claims priority, application France, Apr. 17, 1954,

667,527, Patent 1,698,499; Mar. 28, 1955, 55,163

3 Claims. (Cl. 103161) This application is a division of application Serial No.

130,055, filed August 8, 1961, now Patent No. 3,099,223; 7

openings with a distributor mounted in the axis of the pump body.

One of the objects of the invention is to produced a volumetric pump of the above-mentioned type comprising a distributor with means enabling by a suitable pie-compression of the liquid, the compressibility eifects in the chamber of each cylinder at the beginning of each discharge.

An object of the invention is to produce a volumetric pump in which the distributor is formed of two elements able to be angularly offset in relation to each other combined with means so that these two elements bear hydraulically on each other for reducing friction and taking up play.

According to another object of the invention, the distributor is combined with an automatic device for looking one of the elements in relation to the other, formed by means on which there acts in an opposing manner, on the one hand, the pressure to be compensated, and on the other, by a resilient medium tending to eliminate the correction effect when the pressure is cancelled out.

The volumetric machine enabling the objects of the invention to be carried out has characteristics resulting from the description hereafter and more particularly from the attached claims.

A volumetric machine accordingto the invention is shown, by way of example, in the attached drawings, in which:

FIGURE 1 is an axial sectional view of the pump assembly;

FIG. 2 is a sectional view of the pump taken along the section line IIII of FIG. 1;

FIG. 3 is a sectional view of a pressure adjusting device for the delivery at the corresponding distributor position.

FIGS. 4 and 5 are enlarged sectional views showing the distributor in two operative positions.

Referring to the drawings, the pump comprises a central body 1 having radially extending cylinders 2 which are preferably of an uneven number for each machining. The central body 1 has a centrally located cavity in which a core 3 provided with recesses 21 is located. The core 3 is so adjusted that the recesses 21 constitute the inner ends of the cylinders 2.

The core 3 is also provided with tapered surfaces 4 and 5 which act as hearing points for two distributor members 15 and 16. The entire assembly is mounted in the axis of the pump body. At each side of the core 3 fluid tight rings 6 are provided to prevent leakage between the core 3 and the central body 1.

The body 1 is supported upon bearing 7 located on each side of a plane containing the longitudinal axes of the cylinders. The body 1 is also provided with axles 8 located near its periphery which are parallel to the axis of thebearings around which the levers 9 upon which rollers are mounted oscillate. The oscillation of the levers 9 causes a reciprocation of the pistons 11 by means of ball bearing push rods or the like.

When the engine operates as a pump the pistons 11 travel inwardly during the delivery period and outwardly when liquid is suctioned into the cylinder. When the engine operates as a hydraulic mot-or liquid under pressure is admitted into the, cylinders when the pistons travel outwardly while the discharge of the liquid to the tank 31 takes place upon the reverse movement of the pistons.

The rollers 12 mounted upon the levers 9 roll inside a cam 13 mounted upon the casing 15 in which the body 1 is mounted and the central body has a relative movement with respect to such cam and casing. The cam 13 is in the form of a ring having hollows and small curvature parts in between upon the interior surface thereof which control the displacement of the pistons by the rollers rolling thereon.

The distributor which is mounted at the axis of the pump is formed of two members 15 and 16. The element 15 surrounding the element 16 is angularly fixed. The

element 16 is rotative and furthermore can be displaced axially as will be indicated below for compensating play. These members are respectively concerned with the intake and delivery of liquid when the pump operates as a pump. The members 15 and 16 have tapered portions bearing upon the tapered surfaces 4 and 5 of the central core 3. The core 3 has ports 17 and 18 therein and by means of corresponding ports 17 and 18 carried by the distributor members 15 and 16 the cylinders communicate alternatively with the intake pipe 19 and the delivery pipe 20.

The first portion 15 of the distributor has orifices 17 cooperating with the orifices 17 of the central core 3 and the movable portion 16 of the distributor has orifices 18 cooperating with the orifices 18 carried upon the central core. The orifices 17 are for the admission of liquid into the cylinder and the orifices 18 are for the delivery of liquid across the cylinder in the operation as a pump.

In FIGURE 1 the ports 17, 17 18 and 18 are shown in the case of the cylinder 2 of this figure as being in simultaneous coincidence (which coincidence does not happen in fact).

The recesses 2 forming the ends of the cylinders 2 as 'well as the corresponding ends of the pistons 11 have a wear and expansion are therefore automatically obtained by the relative movement of the two distributor members. For this purpose the member 16 has a cylindrical extension 16 forming a centertube which is located inside the other member 15. The tube 16 and the member 15 form an annular chamber 21 in which the delivery pressure is exterted tending to bringthe members 16 and 15 by suitable pressure to bear upon the surfaces 4 and 5. The checking, of the members 16 and 15 which are individually assigned to high and low pressure can be which is fixed to the extension 16 3. clone independently of one another so as to insure the best filling of the cylinders and the optimum reduction of compressibility eliects.

A partition 1:5 bearing on the auxiliary chock 16;, carried by the distributor 1 5 in the vicinity of its terminal flared part, closes the volume occupied by the liquid under pressure in this part of the distributor and any leakage is prevented by the seal-tight packing of the partition 16 The ports 17 and 18 provided upon the members and 16 for the intake and the delivery thereof outside of the cylinders 2 are uniformly distributed over the periphery of each of the members 15 and 16 in a number equal to the number of bosses or hollows encountered in a complete revolution.

In the distributor, the member 15 is angularly fixed with regard to the cam 13 and the casing 14 by means of the tube 19. The member 16 is capable of limited angular displacement in order to allow compressibility effects at various pressure to be corrected since this member is fixed to the movable piece or lever 26 by the extension 16 as shown in FXGURE l.

The disturbing effects of the compressibility of the fluid evolving in the pump are revealed every time a given volume of fluid is subjected to a sudden pressure variation.

In a distributor pump, these disturbing ellects may thus occur near the end of strokes, at the end of compression, at the beginning of inlet on the one hand, at the end of suction at the beginning of compression on the other, when the pump operates as a generator. As, moreover, the disturbance set up by such ellects is directly function of the amount of the fluid mass undergoing the sudden pressure variation (and hence, the volume).

It is obvious that when the piston is completely inserted in the cylinder, the efiect in question is very small as compared with that when the piston makes its maximum outward movement in the cylinder. This latter case corresponds to the end of the inlet, the beginning of compression. For eliminating the corresponding disturbing effect, it is necessary, at the moment of closing the inlet (closing the openings 17), retarding the opening of the openings 18 up to the moment when, by the displacement of the piston towards the inside of the cylinder, the pressure in the cylinder rises to the value of the delivery pressure such as prevails in the duct 29.

This delay in opening the delivery opening 18 is determined by the angle at which the element 16 is set in relation to the element 15 of the distributor in function of the delivery pressure, this being effected by the correction device shown in FIGURE 3.

This correcting device comprises a cam 22 subjected to the action of an elastic member as for example a torsion bar 23 upon which the cam 22 is mounted. A push rod 24 receiving the delivery pressure acts upon the cam 22 so as to alter its angular position. The maximum displacement is limited by an adjustable stop 25. The cam 22 forms an abutment for the lever 26 carrying a roller The lever 26 drawn back by the spring 27 is controlled by the roller 26 rolling upon the cam which is itself in equilibrium between the push rod 24 and the opposing torsion bar 23.

During the working period the friction of the movable member 16 upon the core 3'tends to apply the roller 2-6 of the lever 26 against the cam 22. At rest the spring 27 returns the roller 26 to the cam. The position of the cam 22 therefore being a function of the delivery pressure, it will be seen that the angular position of the movable member 16 automatically adjusts itself as a function of the and the opposing torque of the torsion bar, square, 23 integral with the cam 22, enable a good approximation to be obtained to the equality of pressures in the cylinder and in the duct 2% at moment when the opening 13 is opened.

What I claim is:

l. in a volumetric machine capable of operating as a fluid generator under pressure or as a motor utilizing fluid under pressure the combination comprising a body, a central core fixed to said body, a plurality of radial cylinders in said body, a cam, a plurality of pistons with alternating movements in said cylinders, means controlled by said cam controlling the alternating movements of each piston, a distributor mounted axially in said body, said distributor comprising a first fixed element, a second angularly movable element, inlet orifices and delivery orifices in said central core communicating with each cylinder, inlet orifices in said fixed element and delivery orifices in said movable element cooperating with said first named inlet and delivery orifices, means controlling the angular position or said movable element with relation to said first fixed element, means for subjecting said elements on one hand to the delivery pressure and on the other hand to elastic pressure.

2. In a volumetric machine capable of operating as a generator for fluid under pressure or as a motor utilizing fluid under pressure the combination comprising a body, a central core fixed to said body, a plurality of radial cylinders in said body, a cam, a plurality of pistons with alternating movements in said cylinders, means controlled by said cam controlling said pistons for the alternating movement of each piston, a distributor mounted axially of said body, said distributor comprising a first fixed element, a second angularly movable element, inlet orifices and delivery orifices in said central core communicating with each cylinder, inlet orifices in said fixed element and delivery orifices in said movable element cooperating with said first named inlet and delivery orifices, means controlling the angular position of said movable element with relation to said first fixed element, means for subjecting said elements in opposing manner on one hand to the delivery pressure and on the other hand to the pressure of an elassubjecting said cam to the action of delivery pressure and means subjecting said cam to an opposing elastic pressure.

3. In a volumetric machine capable of operating as a generator for fluid under pressure or as a motor utilizing fluid under pressure the combination comprising a body, a central core fixed to said body, a plurality of radial cylinders in said body, a cam, a plurality of pistons with alternating movements in said cylinders, means controlled by said cam controlling said pistons for the alternating movement of each piston, a distributor mounted axially of said body, said distributor comprisng a first fixed element, a second angularly movable element, inlet orifices and delivery orifices in said central core communicating with each cylinder, inlet orifices in said fixed element and delivery orifices in said movable element cooperating with said first named inlet and delivery orifices, means controlling the angular position of said movable element with relation to said first fixed element, means for subjecting said elements in opposing manner on one hand to the delivery pressure and on the other hand to the pressure of an elastic element, an annular chamber provided between said fixed element and said movable element of the distributor, means directing the fiuid delivered into said chamber so that the delivery pressure acts for pushing axially one against the other of said two elements of the distributor which allows reducing friction and eliminating play. No references cited.

LAURENCE V. EFNER, Primary Exairziner. 

1. IN A VOLUMETRIC MACHINE CAPABLE OF OPERATING AS A FLUID GENERATOR UNDER PRESSURE OR AS A MOTOR UTILIZING FLUID UNDER PRESSURE THE COMBINATION COMPRISING A BODY, A CENTRAL CORE FIXED TO SAID BODY, A PLURALITY OF RADIAL CYLINDERS IN SAID BODY, A CAM, A PLURALITY OF PISTONS WITH ALTERNATING MOVEMENTS IN SAID CYLINDERS, MEANS CONTROLLED BY SAID CAM CONTROLLING THE ALTERNATING MOVEMENTS OF EACH PISTONS, A DISTRIBUTOR MOUNTED AXIALLY IN SAID BODY, SAID DISTRIBUTOR COMPRISING A FIRST FIXED ELEMENT, A SECOND ANGULARLY MOVABLE ELEMENT, INLET ORIFICES AND DELIVERY ORIFICES IN SAID CENTRAL COMMUNICATING WITH EACH CYLINDER, INLET ORIFICES IN SAID FIXED ELEMENT AND DELIVERY ORIFICES IN SAID MOVABLE ELEMENT COOPERATING WITH SAID FIRST NAMED INLET AND DELIVERY ORIFICES, MEANS CONTROLLING THE ANGULAR POSITION OF SAID MOVABLE ELEMENT WITH RELATION TO SAID FIRST FIXED ELEMENT, MEANS FOR SUBJECTING SAID ELEMENTS ON ONE HAND TO THE DELIVERY PRESSURE AND ON THE OTHER HAND TO ELASTIC PRESSURE. 